Foiling upwind? Say it’s so!

The AC72’s ability to hydrofoil has been the biggest design development of the 34th America’s Cup. So much so, that design teams are focusing more on getting the underwater appendages correct than the 131-foot tall wing sail that powers the speeding catamarans.

Hydrofoiling has enabled the teams to reach speeds of 45 knots off the wind, but the benefits of foiling upwind have been debated back and forth. One camp says it isn’t worth it because too much VMG, the yacht’s theoretical speed directly towards the mark, is lost. Another camp says it’s worth it to crack the sheets a bit, put the bows down and get rumbling.

That’s apparently what Emirates Team New Zealand was doing today on San Francisco Bay.